Heterogeneous catalytic synthesis of poly(butylene succinate) by attapulgite-supported Sn catalyst

An attapulgite-supported Sn catalyst (Sn-palgorskite) was successfully prepared by ion-exchange co-impregnation method. The catalytic effect of Sn-attapulgite on the melt polycondensation reaction of poly(butylene succinate) (PBS) was examined by comparing with that of anhydrous SnCl2 and a blank experiment. The structures and properties of the PBS products synthesized with the three catalytic systems were characterized by means of Fourier transform-infrared spectra (FT-IR), viscosity measurements, wide angle X-ray diffraction (WARD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Meanwhile, the acidolysis degradation behaviors of the PBS samples were also studied. It was found that the intrinsic viscosities and the number-average molecular weights of the PBS were remarkably increased under the catalysis of Sn-attapulgite, further leading to an increase in the decomposition temperature, the crystallization temperature, and the viscous flow activation energy, while a decrease in the melting temperature, the relative degree of crystallinity, and the rate of degradation. Additionally, no significant differences were observed in the crystal structures of all the samples, regardless of the reaction system with or without catalyst. The experiment results confirmed that Sn-attapulgite was an effective heterogeneous catalyst for the synthesis of PBS, and the recycled Sn-attapulgite still exhibited higher activity than anhydrous SnCl2 under identical reaction conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41729.